A10T 3-in-1-out hotend: How many heaters run if using only one extruder?

[JonS]

Hi.

I'm new to the A10T scene, and I recently got a used, slightly malfunctioning A10T. After flashing it with Marlin 2.x, I was able to get extruder # 1 to work properly (I was printing a single color using extruder # 1), however, it appears that the other two extruders are clogged down in the hotend. It almost seemed that only one hotend chamber was heating.

Before I tear the hotend apart, I wanted to get some clarity on how the hotend heats up.

* Are the three heaters in the hotend wired in parallel (i.e., they are either all on together or all off together), or are they individually controlled?

* If individually controlled, then if I'm printing using only one color (only one extruder), are the other heaters running or are they off?

* I've watched the video that shows how to clear the hotend, however, I'm running Marlin so the menus are a little different. If I just select to preheat PLA, will all hotend heaters turn on, or is there something I need to set in the mixing control to force all heaters to run?

Thank you for your time.

-Jon